Calculate the mass fraction of potassium, phosphorus and oxygen in potassium phosphate.

Let’s find the molar mass of the salt and its constituent components:

M K3PO4 = 39 x 3 + 31 + 16 x 4 = 212 grams / mol;

M K3 = 39 x 3 = 117 grams / mol;

M P = 31 grams / mol;

M O3 = 16 x 4 = 64 grams / mol;

Let us find the fractions of the molar masses of the components corresponding to the mass fraction:

Mass fraction of potassium m K = 117/212 = 0.552 = 55.2%;

Mass fraction of phosphorus m P = 31/212 = 0.146 = 14.6%;

Mass fraction of oxygen m О = 64/212 = 0.302 = 30.2%;

Check 55.2 + 14.6 + 30.2 = 100%;